The waveswing picutred at the left is the most elegant wave power solution of many under development.  According to its website:

By 2009 utility-scale AWS machines will be delivering clean and reliable electricity to consumers in several countries including the UK and Portugal. Within 10 years our technology will be adopted by major energy producers across the globe and within 20 years AWS generators will provide a significant contribution to world energy supplies.

With a continuous average output of 1.2MW in a rough sea and total energy production in excess of 4000MWh in a northern Atlantic location the AWS truly is a utility scale generator.

There are adequate wave resource off the west coast of Washington.  Seattle City Light should purchase a pilot plant from AWS or some other provider.